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NB Blasting Training

Scaled Distance Calculator

Calculate SD = D / √W for ground vibration compliance

Input Values

m

From blast point to nearest structure

kg

Maximum explosive charge detonating in same delay

Scaled Distance (SD)
Enter values

Reference Thresholds

Safe threshold≥ 25m/kg⁰·⁵
Caution zone15 - 25m/kg⁰·⁵
Danger zone< 15m/kg⁰·⁵

Formula

SD = D ÷ √W
  • SD = Scaled Distance (m/kg⁰·⁵)
  • D = Distance from blast to receptor (m)
  • W = Max charge weight per delay (kg)

Used to predict ground vibration (PPV) at nearby structures